Review of OSHA's Integrated Management Information System (IMIS) reveals that between 1997 and 2007, 100 accidents were recorded specifically involving skid-steer loaders. The deliberate bypassing of safety features (such as seatbelts and control interlock systems) was identified as the direct cause of 20% of these incidents, with all but one resulting in a fatality. Three cases are described below:
Case 1:
An employee was working alone, operating a skid-steer loader for "fine grading" or smoothing out dirt to provide the final contouring around a new home that was nearing completion. While operating the skid-steer loader, one of the bucket bolt pins, which connects the loader arm to the bucket, fell out. The employee dismounted the vehicle with the engine still running, manually lowered the lap bar safety device, and operated the hydraulic controls from outside the vehicle. The employee was attempting to realign the loader arm hole with the bucket hole and reinsert the bucket bolt pin. In the process, he was trapped between the bucket and the body of the skid-steer loader and was crushed. The employee was found in a position that allowed him to operate the controls from outside the vehicle with the bucket bolt pin and a large hammer nearby.
Upon inspecting the skid-steer loaders on this job site, the following conditions were noted:
The interlock control system was disabled on the unit involved in the accident. This system was intended to prevent the loader’s controls from operating unless the operator was in the proper operating position. The absence of the operator's weight should have deactivated an electronic switch under the seat that allows the loader controls to function when the lap bar is also in a lowered position. The system ensures that the engine stops when the operator leaves the seat of the skid-steer loader or attempts to lower the lap bar to operate the loader controls from outside of the skid-steer loader.
Interlock control systems on other skid-steer loaders on site had also been disabled or were not functioning properly. This condition allowed the operator to activate the loader's controls with the seat bar in the raised position.
Backup alarms did not work on some units.
Seatbelts had been removed from the skid-steer loaders.
The employer received a citation for a serious violation under the General Duty Clause of the Occupational Safety and Health Act (OSH Act) (Section 5(a)(1)).
Case 2:
An employee was ordered by his company to repair a leak in the hydraulic slave cylinder of a skid-steer loader. He drove the skid-steer loader into the warehouse and began the repair. He bypassed the safety bar by jamming it into the interlocks without being seated in the cab. He then started the skid-steer loader and raised the bucket over the cab. Upon exiting the cab, his foot inadvertently pressed the down pedal for the bucket. The bucket came down and trapped him between the lift and the cab. He then hit the left side lever, causing the skid-steer loader to move in reverse. It crashed into a parked forklift and he was killed.
Upon investigation, the three causes of the accident were identified as:
Employee's intentional bypassing of the safety features of the skid-steer loader to perform maintenance,
Failure to use an approved lift arm support device, and
Improper employee training on operating, servicing, or maintaining the skid-steer loader according to the manufacturer's instructions.
The employer received a citation for a serious violation under the General Duty Clause of the OSH Act (Section 5(a)(1)).
Case 3:
An employee at a tractor implement dealership was cleaning debris from a wash bay using a skid-steer loader. This particular skid-steer loader was equipped with a manual seat bar as well as a pressure switch in the seat to detect the presence of an operator. The operator was able to leave the cab to wash the skid-steer loader bucket while it was still operational. The bucket was left sitting on its nose which prevented the loader arms from resting against the body of the vehicle as it was designed to do. This position made it difficult to enter and exit the cab. As the employee attempted to get back into the cab, he slipped and fell face-first into the cab seat. The loader arms dropped and caught him between the body of the skid-steer loader and the loader arms, and he was killed.
The two major contributing factors to this accident were:
Employee's intentional bypassing of the safety systems of the skid-steer loader, and
Improper employee training on the safety features associated with the skid-steer loader. "On-the-job" training did not include a review of the operator's manual.
The employer received a citation for a serious violation under the General Duty Clause of the OSH Act (Section 5(a)(1)).
Conclusion
Properly maintained and functioning seatbelts and control interlock systems are critical to the safe operation of skid-steer loaders. Field reports have shown injuries and fatalities can occur by operating skid-steer loaders with one or both of these safety systems bypassed, disabled, or improperly maintained.